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After transferring from float type to int type, why the number all altered into -1 in python?
How do I parse a string to a float or int in Python?How do I determine the size of an object in Python?Peak detection in a 2D arrayWhy is reading lines from stdin much slower in C++ than Python?Converting a Pandas GroupBy object to DataFrameAdding new column to existing DataFrame in Python pandas“Large data” work flows using pandasAdd new column in pandas data frameNumpy turning ints to decimalsDifferent results from syntax
.everyoneloves__top-leaderboard:empty,.everyoneloves__mid-leaderboard:empty,.everyoneloves__bot-mid-leaderboard:empty height:90px;width:728px;box-sizing:border-box;
This is the code I entered:
df = pd.DataFrame('A': [1.6,1.2,3.9,4.5, np.nan])
df['A'] = df['A'].fillna(-1).astype(int)
for i in df['A']:
df["B"] = i
df
But the result I get is like this:
enter image description here
So why the column B would all appear as -1 instead of the same as column A?
python pandas numpy
edited Mar 8 at 4:44
Spencer Wieczorek
17.6k43345
asked Mar 8 at 4:35
RachelRachel
6
add a comment |
This is the code I entered:
df = pd.DataFrame('A': [1.6,1.2,3.9,4.5, np.nan])
df['A'] = df['A'].fillna(-1).astype(int)
for i in df['A']:
df["B"] = i
df
But the result I get is like this:
enter image description here
So why the column B would all appear as -1 instead of the same as column A?
python pandas numpy
edited Mar 8 at 4:44
Spencer Wieczorek
17.6k43345
asked Mar 8 at 4:35
RachelRachel
6
2
Please add the output in code format, not in image.
– pistol2myhead
Mar 8 at 4:36
add a comment |
This is the code I entered:
df = pd.DataFrame('A': [1.6,1.2,3.9,4.5, np.nan])
df['A'] = df['A'].fillna(-1).astype(int)
for i in df['A']:
df["B"] = i
df
But the result I get is like this:
enter image description here
So why the column B would all appear as -1 instead of the same as column A?
python pandas numpy
edited Mar 8 at 4:44
Spencer Wieczorek
17.6k43345
asked Mar 8 at 4:35
RachelRachel
6
This is the code I entered:
df = pd.DataFrame('A': [1.6,1.2,3.9,4.5, np.nan])
df['A'] = df['A'].fillna(-1).astype(int)
for i in df['A']:
df["B"] = i
df
But the result I get is like this:
enter image description here
So why the column B would all appear as -1 instead of the same as column A?
python pandas numpy
python pandas numpy
edited Mar 8 at 4:44
Spencer Wieczorek
17.6k43345
asked Mar 8 at 4:35
RachelRachel
6
edited Mar 8 at 4:44
Spencer Wieczorek
17.6k43345
asked Mar 8 at 4:35
RachelRachel
6
edited Mar 8 at 4:44
Spencer Wieczorek
17.6k43345
edited Mar 8 at 4:44
Spencer Wieczorek
17.6k43345
edited Mar 8 at 4:44
Spencer Wieczorek
17.6k43345
17.6k43345
asked Mar 8 at 4:35
RachelRachel
6
asked Mar 8 at 4:35
RachelRachel
6
asked Mar 8 at 4:35
RachelRachel
6
6
2
Please add the output in code format, not in image.
– pistol2myhead
Mar 8 at 4:36
add a comment |
2
Please add the output in code format, not in image.
– pistol2myhead
Mar 8 at 4:36
2
2
Please add the output in code format, not in image.
– pistol2myhead
Mar 8 at 4:36
Please add the output in code format, not in image.
– pistol2myhead
Mar 8 at 4:36
add a comment |
3 Answers
3
active
oldest
votes
You are setting the entire column to i with df["B"] = i. In your last iteration, i is -1, so your entire column B is set to -1.
If you want to set B to A, you can just use this (no for loop needed):
df['B'] = df['A']
answered Mar 8 at 4:41
busybearbusybear
3,71011027
add a comment |
In your for loop you reassign the entire value of df["B"] each time. The last value in df['A'] (np.nan) when converted to a int is -1. Since you are setting df["B"] as a whole all the value are assigned as -1.
answered Mar 8 at 4:42
Spencer WieczorekSpencer Wieczorek
17.6k43345
add a comment |
Change
for i in df['A']:
df["B"] = i
to
for i, item in df['A'].items():
df.ix[i, "B"] = item
answered Mar 8 at 7:21
hacker315hacker315
563213
add a comment |
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3 Answers
3
active
oldest
votes
3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
You are setting the entire column to i with df["B"] = i. In your last iteration, i is -1, so your entire column B is set to -1.
If you want to set B to A, you can just use this (no for loop needed):
df['B'] = df['A']
answered Mar 8 at 4:41
busybearbusybear
3,71011027
add a comment |
You are setting the entire column to i with df["B"] = i. In your last iteration, i is -1, so your entire column B is set to -1.
If you want to set B to A, you can just use this (no for loop needed):
df['B'] = df['A']
answered Mar 8 at 4:41
busybearbusybear
3,71011027
add a comment |
You are setting the entire column to i with df["B"] = i. In your last iteration, i is -1, so your entire column B is set to -1.
If you want to set B to A, you can just use this (no for loop needed):
df['B'] = df['A']
answered Mar 8 at 4:41
busybearbusybear
3,71011027
You are setting the entire column to i with df["B"] = i. In your last iteration, i is -1, so your entire column B is set to -1.
If you want to set B to A, you can just use this (no for loop needed):
df['B'] = df['A']
answered Mar 8 at 4:41
busybearbusybear
3,71011027
answered Mar 8 at 4:41
busybearbusybear
3,71011027
answered Mar 8 at 4:41
busybearbusybear
3,71011027
answered Mar 8 at 4:41
busybearbusybear
3,71011027
3,71011027
add a comment |
add a comment |
In your for loop you reassign the entire value of df["B"] each time. The last value in df['A'] (np.nan) when converted to a int is -1. Since you are setting df["B"] as a whole all the value are assigned as -1.
answered Mar 8 at 4:42
Spencer WieczorekSpencer Wieczorek
17.6k43345
add a comment |
In your for loop you reassign the entire value of df["B"] each time. The last value in df['A'] (np.nan) when converted to a int is -1. Since you are setting df["B"] as a whole all the value are assigned as -1.
answered Mar 8 at 4:42
Spencer WieczorekSpencer Wieczorek
17.6k43345
add a comment |
In your for loop you reassign the entire value of df["B"] each time. The last value in df['A'] (np.nan) when converted to a int is -1. Since you are setting df["B"] as a whole all the value are assigned as -1.
answered Mar 8 at 4:42
Spencer WieczorekSpencer Wieczorek
17.6k43345
In your for loop you reassign the entire value of df["B"] each time. The last value in df['A'] (np.nan) when converted to a int is -1. Since you are setting df["B"] as a whole all the value are assigned as -1.
answered Mar 8 at 4:42
Spencer WieczorekSpencer Wieczorek
17.6k43345
answered Mar 8 at 4:42
Spencer WieczorekSpencer Wieczorek
17.6k43345
answered Mar 8 at 4:42
Spencer WieczorekSpencer Wieczorek
17.6k43345
answered Mar 8 at 4:42
Spencer WieczorekSpencer Wieczorek
17.6k43345
17.6k43345
add a comment |
add a comment |
Change
for i in df['A']:
df["B"] = i
to
for i, item in df['A'].items():
df.ix[i, "B"] = item
answered Mar 8 at 7:21
hacker315hacker315
563213
add a comment |
Change
for i in df['A']:
df["B"] = i
to
for i, item in df['A'].items():
df.ix[i, "B"] = item
answered Mar 8 at 7:21
hacker315hacker315
563213
add a comment |
Change
for i in df['A']:
df["B"] = i
to
for i, item in df['A'].items():
df.ix[i, "B"] = item
answered Mar 8 at 7:21
hacker315hacker315
563213
Change
for i in df['A']:
df["B"] = i
to
for i, item in df['A'].items():
df.ix[i, "B"] = item
answered Mar 8 at 7:21
hacker315hacker315
563213
answered Mar 8 at 7:21
hacker315hacker315
563213
answered Mar 8 at 7:21
hacker315hacker315
563213
answered Mar 8 at 7:21
hacker315hacker315
563213
563213
add a comment |
add a comment |
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2
Please add the output in code format, not in image.
– pistol2myhead
Mar 8 at 4:36