Python iteration slow - python

I have made the following code:
from math import sqrt
import time
def factors(n):
x=(set(reduce(list.__add__,
([i, n//i] for i in range(1, int(n**0.5) + 1) if n % i == 0))))
return sorted(x,reverse=True)
n=10**7
m=0
start_time = time.time()
for i in xrange(1,int(sqrt(n))+1):
l=0
x=factors(i)
for d in xrange(i,n/i+1):
if i==d:
l+=i
else:
for b in x:
if d%b==0:
l+=2*b
break
m+=l
print i
elapsed_time = time.time() - start_time
print elapsed_time
print m
I think what the code does is add the greatest common divisor of i and d for all id≤n
Due to the "print i", I have realized that when i is small the second loop is slow. Why is this?, and how do I optimize?
I see that the iteration over d will be larger, but shouldn't it essentially just be iterating over all the values, whereas for the larger i, the third loop should take a longer time because of the greater size of x.

Could the second loop be slower for small values of i just because the xrange "spans" a larger amount of values for small i?
I mean, in the second loop declaration we have:
for d in xrange(i,n/i+1):
And the maximum value of the xrange (this is, n/i+1) is larger for small i (the quotient n/i is maximum at i=1, then it decreases

Your ideas about how long each loop should take to run a single time relative to one another are accurate, but the differences in them is minimal.
Your assumptions about how many times each loop is running are off by several orders of magnitude.
Loop i is executing ~3000 times. The total number of loop executions called per i varies but on average drops at an high rate. At the start, the d loop is getting called ~ 10,000,000 per i and then it drops off very quickly:
The total number of loops you run for i[0:215] is greater than i[215:3161]
i d_loops b_loops running_mean avg_last_10_loops
1 10000001 1 10000001.0 10000001.0
2 5000001 2 10000001.5 10000001.5
3 3333334 2 8888890.33333 8888890.33333
4 2500001 3 8541668.5 8541668.5
5 2000001 2 7633335.2 7633335.2
6 1666667 4 7472224.0 7472224.0
7 1428572 2 6812926.85714 6812926.85714
8 1250001 4 6586311.5 6586311.5
9 1111112 3 6224869.77778 6224869.77778
10 1000001 4 6002383.2 6002383.2
99 101011 6 1653200.16162 637628.2
199 50252 2 1035550.34171 324231.5
299 33445 4 779296.658863 203848.2
399 25063 8 634848.313283 192922.4
499 20041 2 540089.59519 149790.4
599 16695 2 472549.51586 114461.6
699 14307 4 421785.891273 103772.2
799 12516 4 382086.017522 100739.8
899 11124 4 349883.460512 80518.2
999 10011 8 323351.570571 80530.4
1099 9100 4 300961.77434 67638.0
1199 8341 4 281811.0 61978.2
1299 7699 4 265260.015396 65681.9
1399 7148 2 250684.336669 54528.4
1499 6672 2 237863.799199 49524.2
1599 6254 8 226449.282051 56452.4
1699 5886 2 216141.950559 47237.4
1799 5559 4 206859.735964 43485.8
1899 5266 6 198471.47762 49653.2
1999 5003 2 190769.076538 38112.8
2099 4765 2 183702.581706 34396.0
2199 4548 4 177231.36653 36467.0
2299 4350 6 171250.213136 35741.6
2399 4169 2 165683.010838 34256.8
2499 4002 12 160541.983994 39293.2
2599 3848 4 155707.039246 35478.6
2699 3706 2 151193.218229 27470.6
2799 3573 6 146973.628796 30790.8
2899 3450 4 143019.365643 29714.8
2999 3335 2 139271.870957 28064.8
3099 3227 4 135755.08777 27799.4
3153 3172 4 133946.542341 33037.6
3154 3171 8 133912.116677 30484.8
3155 3170 4 133873.691284 29208.8
3156 3169 12 133843.321926 29196.8
3157 3168 8 133808.95407 30460.0
3158 3167 4 133770.594047 29820.6
3159 3166 12 133740.27477 32349.4
3160 3165 16 133713.977215 25983.4
3161 3164 4 133675.679848 25979.4
3162 3163 16 133649.409235 27867.2

Related

Make loop iterate through range but limited to input

I'm new to python so I apologize in advance if the question is too easy.
I'm trying to make a simulation to find the optimization point on a dataframe. This is what I have so far:
import random
import pandas as pd
import math
import numpy as np
loops = int(input('Q of simulations: '))
cost = 175
sell_price = 250
sale_price = 250/2
# order = 1000
simulation = 0
profit = 0
rows = []
order = range(1000, 3000)
ordenes = []
for i in order:
ordenes.append(i)
for i in ordenes:
demand = math.trunc(1000 + random.random() * (2001))
if demand >= i:
profit = (sell_price - cost)* i
rows.append([simulation, demand, i, profit, (demand - i)])
else:
profit = (sell_price - cost)* demand - (i - demand)* (sale_price - cost)
rows.append([simulation, demand, i, profit, (demand - i)])
DataFrame = pd.DataFrame(rows, columns = ['#Simulation', 'Demand', 'Order', 'Utility', 'Shortage'])
print(DataFrame)
DataFrame.loc[DataFrame['Utility'].idxmax()]
The current output (for any number specified in tis:
#Simulation Demand Order Utility Shortage
0 0 2067 1000 75000.0 1067
1 0 1392 1001 75075.0 391
2 0 1042 1002 75150.0 40
3 0 1457 1003 75225.0 454
4 0 1930 1004 75300.0 926
... ... ... ... ... ...
1995 0 1823 2995 195325.0 -1172
1996 0 2186 2996 204450.0 -810
1997 0 1384 2997 184450.0 -1613
1998 0 1795 2998 194775.0 -1203
1999 0 1611 2999 190225.0 -1388
[2000 rows x 5 columns]
#Simulation 0.0
Demand 2922.0
Order 2989.0
Utility 222500.0
Shortage -67.0
Name: 1989, dtype: float64
Desired Output (writing 5 in the input):
#Simulation Demand Order Utility Shortage
0 0 2067 1000 75000.0 1067
1 1 1392 1001 75075.0 391
2 2 1042 1002 75150.0 40
3 3 1457 1003 75225.0 454
4 4 1930 1004 75300.0 926
[5 rows x 5 columns]
#Simulation 4.0
Demand 1930.0
Order 1004.0
Utility 75300.0
Shortage 926.0
Name: 1989, dtype: float64
I really don't know how to make it happen, I've tried everything that comes to my mind but the outcome either fails on the 'order' column or as shown above.

Trying to lookup a value from a pandas dataframe within a range of two rows in the index dataframe

I have two dataframes - "grower_moo" and "pricing" in a Python notebook to analyze harvested crops and price payments to the growers.
pricing is the index dataframe, and grower_moo has various unique load tickets with information about each load.
I need to pull the price per ton from the pricing index to a new column in the load data if the Fat of that load is not greater than the next Wet Fat.
Below is a .head() sample of each dataframe and the code I tried. I received a ValueError: Can only compare identically-labeled Series objects error.
pricing
Price_Per_Ton Wet_Fat
0 306 10
1 339 11
2 382 12
3 430 13
4 481 14
5 532 15
6 580 16
7 625 17
8 665 18
9 700 19
10 728 20
11 750 21
12 766 22
13 778 23
14 788 24
15 797 25
grower_moo
Load Ticket Net Fruit Weight Net MOO Percent_MOO Fat
0 L2019000011817 56660 833 1.448872 21.92
1 L2019000011816 53680 1409 2.557679 21.12
2 L2019000011815 53560 1001 1.834644 21.36
3 L2019000011161 62320 2737 4.207080 21.41
4 L2019000011160 57940 1129 1.911324 20.06
grower_moo['price_per_ton'] = max(pricing[pricing['Wet_Fat'] < grower_moo['Fat']]['Price_Per_Ton'])
Example output - grower_moo['Fat'] of 13.60 is less than 14 Fat, therefore gets a price per ton of $430
grower_moo_with_price
Load Ticket Net Fruit Weight Net MOO Percent_MOO Fat price_per_ton
0 L2019000011817 56660 833 1.448872 21.92 750
1 L2019000011816 53680 1409 2.557679 21.12 750
2 L2019000011815 53560 1001 1.834644 21.36 750
3 L2019000011161 62320 2737 4.207080 21.41 750
4 L2019000011160 57940 1129 1.911324 20.06 728
This looks like a job for an "as of" merge, pd.merge_asof (documentation):
This is similar to a left-join except that we match on nearest key
rather than equal keys. Both DataFrames must be sorted by the key.
For each row in the left DataFrame:
A "backward" search [the default]
selects the last row in the right DataFrame whose ‘on’ key is less
than or equal to the left’s key.
In the following code, I use your example inputs, but with column names using underscores _ instead of spaces .
# Required by merge_asof: sort keys in left DataFrame
grower_moo = grower_moo.sort_values('Fat')
# Required by merge_asof: key column data types must match
pricing['Wet_Fat'] = pricing['Wet_Fat'].astype('float')
# Perform the asof merge
res = pd.merge_asof(grower_moo, pricing, left_on='Fat', right_on='Wet_Fat')
# Print result
res
Load_Ticket Net_Fruit_Weight Net_MOO Percent_MOO Fat Price_Per_Ton Wet_Fat
0 L2019000011160 57940 1129 1.911324 20.06 728 20.0
1 L2019000011816 53680 1409 2.557679 21.12 750 21.0
2 L2019000011815 53560 1001 1.834644 21.36 750 21.0
3 L2019000011161 62320 2737 4.207080 21.41 750 21.0
4 L2019000011817 56660 833 1.448872 21.92 750 21.0
# Optional: drop the key column from the right DataFrame
res.drop(columns='Wet_Fat')
Load_Ticket Net_Fruit_Weight Net_MOO Percent_MOO Fat Price_Per_Ton
0 L2019000011160 57940 1129 1.911324 20.06 728
1 L2019000011816 53680 1409 2.557679 21.12 750
2 L2019000011815 53560 1001 1.834644 21.36 750
3 L2019000011161 62320 2737 4.207080 21.41 750
4 L2019000011817 56660 833 1.448872 21.92 750
concat_df = pd.concat([grower_moo, pricing], axis)
cocnat_df = concat_df[concat_df['Wet_Fat'] < concat_df['Fat']]
del cocnat_df['Wet_Fat']

Calculate mean values from pandas dataframe

I am trying to find a good way to calculate mean values from values in a dataframe. It contains measured data from an experiment and is imported from an excel sheet. The columns contain the time passed by, electric current and the corresponding voltage.
The current is changed in steps and then held for some time (the current values vary a little bit, so they are not exactly the same for each step). Now I want to calculate the mean voltage for each current step. Since it takes some time after the voltage gets stable after a step, I also want to leave out the first few voltage values after a step.
Currently I am doing this with loops, but I was wondering wether there is a nicer way with the usage of the groupby function (or others maybe).
Just say if you need more details or clarification.
Example of data:
s [A] [V]
0 6.0 -0.001420 0.780122
1 12.0 -0.002484 0.783297
2 18.0 -0.001478 0.785870
3 24.0 -0.001256 0.793559
4 30.0 -0.001167 0.806086
5 36.0 -0.000982 0.815364
6 42.0 -0.003038 0.825018
7 48.0 -0.001174 0.831739
8 54.0 0.000478 0.838861
9 60.0 -0.001330 0.846086
10 66.0 -0.001456 0.851556
11 72.0 0.000764 0.855950
12 78.0 -0.000916 0.859778
13 84.0 -0.000916 0.859778
14 90.0 -0.001445 0.863569
15 96.0 -0.000287 0.864303
16 102.0 0.000056 0.865080
17 108.0 -0.001119 0.865642
18 114.0 -0.000843 0.866434
19 120.0 -0.000997 0.866809
20 126.0 -0.001243 0.866964
21 132.0 -0.002238 0.867180
22 138.0 -0.001015 0.867177
23 144.0 -0.000604 0.867505
24 150.0 0.000507 0.867571
25 156.0 -0.001569 0.867525
26 162.0 -0.001569 0.867525
27 168.0 -0.001131 0.866756
28 174.0 -0.001567 0.866884
29 180.0 -0.002645 0.867240
.. ... ... ...
242 1708.0 24.703866 0.288902
243 1714.0 26.469208 0.219226
244 1720.0 26.468838 0.250437
245 1726.0 26.468681 0.254972
246 1732.0 26.468173 0.271525
247 1738.0 26.468260 0.247282
248 1744.0 26.467666 0.296894
249 1750.0 26.468085 0.247300
250 1756.0 26.468085 0.247300
251 1762.0 26.467808 0.261096
252 1768.0 26.467958 0.259615
253 1774.0 26.467828 0.260871
254 1780.0 28.232325 0.185291
255 1786.0 28.231697 0.197642
256 1792.0 28.231170 0.172802
257 1798.0 28.231103 0.170685
258 1804.0 28.229453 0.184009
259 1810.0 28.230816 0.181833
260 1816.0 28.230913 0.188348
261 1822.0 28.230609 0.178440
262 1828.0 28.231144 0.168507
263 1834.0 28.231144 0.168507
264 1840.0 8.813723 0.641954
265 1846.0 8.814301 0.652373
266 1852.0 8.818517 0.651234
267 1858.0 8.820255 0.637536
268 1864.0 8.821443 0.628136
269 1870.0 8.823643 0.636616
270 1876.0 8.823297 0.635422
271 1882.0 8.823575 0.622253
Output:
s [A] [V]
0 303.000000 -0.000982 0.857416
1 636.000000 0.879220 0.792504
2 699.000000 1.759356 0.752446
3 759.000000 3.519479 0.707161
4 816.000000 5.278372 0.669020
5 876.000000 7.064800 0.637848
6 939.000000 8.828799 0.611196
7 999.000000 10.593054 0.584402
8 1115.333333 12.357359 0.556127
9 1352.000000 14.117167 0.528826
10 1382.000000 15.882287 0.498577
11 1439.000000 17.646748 0.468379
12 1502.000000 19.410817 0.437342
13 1562.666667 21.175572 0.402381
14 1621.000000 22.939826 0.365724
15 1681.000000 24.704600 0.317134
16 1744.000000 26.468235 0.256047
17 1807.000000 28.231037 0.179606
18 1861.000000 8.819844 0.638190
The current approach:
df = df[['s','[A]','[V]']]
#Looping over the rows to separate current points
b=df['[A]'].iloc[0]
start=0
list = []
for index, row in df.iterrows():
if not math.isclose(row['[A]'], b, abs_tol=1e-02):
b=row['[A]']
list.append(df.iloc[start:index])
start=index
list.append(df.iloc[start:])
#Deleting first few points after each current change
list_b = []
for l in list:
list_b.append(l.iloc[3:])
#Calculating mean values for each current point
list_c = []
for l in list_b:
list_c.append(l.mean())
result=pd.DataFrame(list_c)
Does this help?
df.groupby(['Columnname', 'Columnname2']).mean()
You may need to create intermediate dataframes for each step. Can you provide an example of the output you want?

compare 2 dataframe with pandas

It is the first time I use pandas and I do not really know how to deal with my problematic.
In fact I have 2 data frame:
import pandas
blast=pandas.read_table("blast")
cluster=pandas.read_table("cluster")
Here is an exemple of their contents:
>>> cluster
cluster_name seq_names
0 1 g1.t1_0035
1 1 g1.t1_0035_0042
2 119365 g1.t1_0042
3 90273 g1.t1_0042_0035
4 71567 g10.t1_0035
5 37976 g10.t1_0035_0042
6 22560 g10.t1_0042
7 90280 g10.t1_0042_0035
8 82698 g100.t1_0035
9 47392 g100.t1_0035_0042
10 28484 g100.t1_0042
11 22580 g100.t1_0042_0035
12 19474 g1000.t1_0035
13 5770 g1000.t1_0035_0042
14 29708 g1000.t1_0042
15 99776 g1000.t1_0042_0035
16 6283 g10000.t1_0035
17 39828 g10000.t1_0035_0042
18 25383 g10000.t1_0042
19 106614 g10000.t1_0042_0035
20 6285 g10001.t1_0035
21 13866 g10001.t1_0035_0042
22 121157 g10001.t1_0042
23 106615 g10001.t1_0042_0035
24 6286 g10002.t1_0035
25 113 g10002.t1_0035_0042
26 25397 g10002.t1_0042
27 106616 g10002.t1_0042_0035
28 4643 g10003.t1_0035
29 13868 g10003.t1_0035_0042
... ... ...
and
[78793 rows x 2 columns]
>>> blast
qseqid sseqid pident length mismatch \
0 g1.t1_0035_0042 g1.t1_0035_0042 100.0 286 0
1 g1.t1_0035_0042 g1.t1_0035 100.0 257 0
2 g1.t1_0035_0042 g9307.t1_0035 26.9 134 65
3 g2.t1_0035_0042 g2.t1_0035_0042 100.0 445 0
4 g2.t1_0035_0042 g2.t1_0035 95.8 451 3
5 g2.t1_0035_0042 g24520.t1_0042_0035 61.1 429 137
6 g2.t1_0035_0042 g9924.t1_0042 61.1 429 137
7 g2.t1_0035_0042 g1838.t1_0035 86.2 29 4
8 g3.t1_0035_0042 g3.t1_0035_0042 100.0 719 0
9 g3.t1_0035_0042 g3.t1_0035 84.7 753 62
10 g4.t1_0035_0042 g4.t1_0035_0042 100.0 242 0
11 g4.t1_0035_0042 g3.t1_0035 98.8 161 2
12 g5.t1_0035_0042 g5.t1_0035_0042 100.0 291 0
13 g5.t1_0035_0042 g3.t1_0035 93.1 291 0
14 g6.t1_0035_0042 g6.t1_0035_0042 100.0 152 0
15 g6.t1_0035_0042 g4.t1_0035 100.0 152 0
16 g7.t1_0035_0042 g7.t1_0035_0042 100.0 216 0
17 g7.t1_0035_0042 g5.t1_0035 98.1 160 3
18 g7.t1_0035_0042 g11143.t1_0042 46.5 230 99
19 g7.t1_0035_0042 g27537.t1_0042_0035 40.8 233 111
20 g3778.t1_0035_0042 g3778.t1_0035_0042 100.0 86 0
21 g3778.t1_0035_0042 g6174.t1_0035 98.0 51 1
22 g3778.t1_0035_0042 g20037.t1_0035_0042 100.0 50 0
23 g3778.t1_0035_0042 g37190.t1_0035 100.0 50 0
24 g3778.t1_0035_0042 g15112.t1_0042_0035 66.0 53 18
25 g3778.t1_0035_0042 g6061.t1_0042 66.0 53 18
26 g18109.t1_0035_0042 g18109.t1_0035_0042 100.0 86 0
27 g18109.t1_0035_0042 g33071.t1_0035 100.0 81 0
28 g18109.t1_0035_0042 g32810.t1_0035 96.4 83 3
29 g18109.t1_0035_0042 g17982.t1_0035_0042 98.6 72 1
... ... ... ... ... ...
if you stay focus on the cluster database, the first column correspond to the cluster ID and inside those clusters there are several sequences ID.
What I need to to is first to split all my cluster (in R it would be like: liste=split(x = data$V2, f = data$V1) )
And then, creat a function which displays the most similarity paires sequence within each cluster.
here is an exemple:
let's say I have two clusters (dataframe cluster):
cluster 1:
seq1
seq2
seq3
seq4
cluster 2:
seq5
seq6
seq7
...
On the blast dataframe there is on the 3th column the similarity between all sequences (all against all), so something like:
seq1 vs seq1 100
seq1 vs seq2 90
seq1 vs seq3 56
seq1 vs seq4 49
seq1 vs seq5 40
....
seq2 vs seq3 70
seq2 vs seq4 98
...
seq5 vs seq5 100
seq5 vs seq6 89
seq5 vs seq7 60
seq7 vs seq7 46
seq7 vs seq7 100
seq6 vs seq6 100
and what I need to get is :
cluster 1 (best paired sequences):
seq 1 vs seq 2
cluster2 (best paired sequences):
seq 5 vs seq6
...
So as you can see, I do not want to take into account the sequences paired by themselves
IF someone could give me some clues it would be fantastic.
Thank you all.
Firstly I assume that there are no Pairings in 'blast' with sequences from two different Clusters. In other words: in this solution the cluster-ID of a pairing will be evaluated by only one of the two sequence IDs.
Including cluster information and pairing information into one dataframe:
data = cluster.merge(blast, left_on='seq_names', right_on='qseqid')
Then the data should only contain pairings of different sequences:
data = data[data['qseqid']!=data['sseqid']]
To ignore pairings which have the same substrings in their seqid, the most readable way would be to add data columns with these data:
data['qspec'] = [seqid.split('_')[1] for seqid in data['qseqid'].values]
data['sspec'] = [seqid.split('_')[1] for seqid in data['sseqid'].values]
Now equal spec-values can be filtered the same way like it was done with equal seqids above:
data = data[data['qspec']!=data['sspec']]
In the end the data should be grouped by cluster-ID and within each group, the maximum of pident is of interest:
data_grpd = data.groupby('cluster_name')
result = data.loc[data_grpd['pident'].idxmax()]
The only drawback here - except the above mentioned assumption - is, that if there are several exactly equal max-values, only one of them would be taken into account.
Note: if you don't want the spec-columns to be of type string, you could easiliy turn them into integers on the fly by:
import numpy as np
data['qspec'] = [np.int(seqid.split('_')[1]) for seqid in data['qseqid'].values]
This merges the dataframes based first on sseqid, then on qseqid, and then returns results_df. Any with 100% match are filtered out. Let me know if this works. You can then order by cluster name.
blast = blast.loc[blast['pident'] != 100]
results_df = cluster.merge(blast, left_on='seq_names',right_on='sseqid')
results_df = results_df.append(cluster.merge(blast, left_on='seq_names',right_on='qseqid'))

How to place each elements of any column exactlty underneath each other? [duplicate]

This question already has answers here:
Create nice column output in python
(22 answers)
Closed 5 years ago.
I have a problem that in the output of my code;
elements of each column does not place exactly beneath each other.
My original code is too busy, so I reduce it to a simple one;
so at first les's explain this simple one:
At first consider one simple question as follows:
Write a code which recieves a natural number r, as number of rows;
and recieves another natural number c, as number of columns;
and then print all natural numbers
form 1 to rc in r rows and c columns.
So the code will be something like the following:
r = int(input("How many Rows? ")); ## here r stands for number of rows
c = int(input("How many columns? ")); ## here c stands for number of columns
for i in range(1,r+1):
for j in range (1,c+1):
print(j+c*(i-1)) ,
print
and the output is as follows:
How many Rows? 5
How many columns? 6
1 2 3 4 5 6
7 8 9 10 11 12
13 14 15 16 17 18
19 20 21 22 23 24
25 26 27 28 29 30
>>>
or:
How many Rows? 7
How many columns? 3
1 2 3
4 5 6
7 8 9
10 11 12
13 14 15
16 17 18
19 20 21
>>>
What should I do, to get an output like this?
How many Rows? 5
How many columns? 6
1 2 3 4 5 6
7 8 9 10 11 12
13 14 15 16 17 18
19 20 21 22 23 24
25 26 27 28 29 30
>>>
or
How many Rows? 7
How many columns? 3
1 2 3
4 5 6
7 8 9
10 11 12
13 14 15
16 17 18
19 20 21
>>>
Now my original code is somthing like the following:
def function(n):
R=0;
something...something...something...
something...something...something...
something...something...something...
something...something...something...
return(R)
r = int(input("How many Rows? ")); ## here r stands for number of rows
c = int(input("How many columns? ")); ## here c stands for number of columns
for i in range(0,r+1):
for j in range(0,c+1)
n=j+c*(i-1);
r=function(n);
print (r)
Now for simplicity, suppose that by some by-hand-manipulation we get:
f(1)=function(1)=17, f(2)=235, f(3)=-8;
f(4)=-9641, f(5)=54278249, f(6)=411;
Now when I run the code the out put is as follows:
How many Rows? 2
How many columns? 3
17
235
-8
-9641
54278249
41
>>>
What shold I do to get an output like this:
How many Rows? 2
How many columns? 3
17 235 -8
-9641 54278249 411
>>>
Also note that I did not want to get something like this:
How many Rows? 2
How many columns? 3
17 235 -8
-9641 54278249 411
>>>
Use rjust method:
r,c = 5,5
for i in range(1,r+1):
for j in range (1,c+1):
str_to_printout = str(j+c*(i-1)).rjust(2)
print(str_to_printout),
print
Result:
1 2 3 4 5
6 7 8 9 10
11 12 13 14 15
16 17 18 19 20
21 22 23 24 25
UPD.
As for your last example, let's say f(n) is defined in this way:
def f(n):
my_dict = {1:17, 2:235, 3:-8, 4:-9641, 5:54278249, 6:411}
return my_dict.get(n, 0)
Then you can use the following approach:
r,c = 2,3
# data table with elemets in string format
data_str = [[str(f(j+c*(i-1))) for j in range (1,c+1)] for i in range(1,r+1)]
# transposed data table and list of max len for every column in data_str
data_str_transposed = [list(i) for i in zip(*data_str)]
max_len_columns = [max(map(len, col)) for col in data_str_transposed]
# printing out
# the string " " before 'join' is a delimiter between columns
for row in data_str:
print(" ".join(elem.rjust(max_len) for elem, max_len in zip(row, max_len_columns)))
Result:
17 235 -8
-9641 54278249 411
With r,c = 3,3:
17 235 -8
-9641 54278249 411
0 0 0
Note that the indent in each column corresponds to the maximum length in this column, and not in the entire table.
Hope this helps. Please comment if you need any further clarifications.
# result stores the final matrix
# max_len stores the length of maximum element
result, max_len = [], 0
for i in range(1, r + 1):
temp = []
for j in range(1, c + 1):
n = j + c * (i - 1);
r = function(n);
if len(str(r)) > max_len:
max_len = len(str(r))
temp.append(r)
result.append(temp)
# printing the values seperately to apply rjust() to each and every element
for i in result:
for j in i:
print(str(j).rjust(max_len), end=' ')
print()
Adopted from MaximTitarenko's answer:
You first look for the minimum and maximum value, then decide which is the longer one and use its length as the value for the rjust(x) call.
import random
r,c = 15,5
m = random.sample(xrange(10000), 100)
length1 = len(str(max(m)))
length2 = len(str(min(m)))
longest = max(length1, length2)
for i in range(r):
for j in range (c):
str_to_printout = str(m[i*c+j]).rjust(longest)
print(str_to_printout),
print
Example output:
937 9992 8602 4213 7053
1957 9766 6704 8051 8636
267 889 1903 8693 5565
8287 7842 6933 2111 9689
3948 428 8894 7522 417
3708 8033 878 4945 2771
6393 35 9065 2193 6797
5430 2720 647 4582 3316
9803 1033 7864 656 4556
6751 6342 4915 5986 6805
9490 2325 5237 8513 8860
8400 1789 2004 4500 2836
8329 4322 6616 132 7198
4715 193 2931 3947 8288
1338 9386 5036 4297 2903
You need to use the string method .rjust
From the documentation (linked above):
string.rjust(s, width[, fillchar])
This function right-justifies a string in a field of given width. It returns a string that is at least width characters wide, created by padding the string with the character fillchar (default is a space) until the given width on the right. The string is never truncated.
So we need to calculate what the width (in characters) each number should be padded to. That is pretty simple, just the number of rows * number of columns + 1 (the +1 adds a one-space gab between each column).
Using this, it becomes quite simple to write the code:
r = int(input("How many Rows? "))
c = int(input("How many columns? "))
width = len(str(r*c)) + 1
for i in range(1,r+1):
for j in range(1,c+1):
print str(j+c*(i-1)).rjust(width) ,
print
which for an r, c of 4, 5 respectively, outputs:
1 2 3 4 5
6 7 8 9 10
11 12 13 14 15
16 17 18 19 20
Hopefully this helps you out and you can adapt this to other situations yourself!

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